A new study from the Harris School of Public Policy at the University of Chicago has analysed the impact of stay-at-home orders on infections and deaths in U.S. states and found they made no difference.
The peer-reviewed study, published in the scientific journal PNAS, found stay-at-home orders (also known as shelter-in-place orders or SIPs) were not associated with lower infections or deaths; furthermore, they were actually associated with a slight increase in infections and deaths, although this was not statistically significant. The results are summarised in the charts below, where dots above the dashed line indicate an increase and dots below a decrease. Red dots are statistically significant results.
The authors suggest that stay-at-home orders have no impact on infections or deaths because they have little to no impact on mobility. Isolating the impact of stay-at-home orders from existing mobility trends, they estimate that the orders themselves contributed a reduction in mobility of just 0.7% compared to pre-pandemic levels. This is largely, they say, because people were already reducing their mobility as much as they were able or willing to.
The mobility data (from mobile phone movement) for U.S. states, with the date of the stay-at-home order shown as a dashed line ands its removal as a dotted line, are shown below.
The authors observe that if stay-at-home orders aren’t affecting mobility, it’s difficult to see how they will affect anything else: “If SIP [shelter-in-place] orders did not have large effects on behaviour, it is hard to imagine how they could have had large effects on COVID-19 cases and deaths.” They add: “The health benefits of SIP orders were likely limited because many people were already social distancing before the introduction of SIP orders.”
They suggest that voluntary mobility reduction and social distancing made a difference to outcomes, though do not commit to saying how much. Noting that nationwide there was around a 50% decrease in mobility between February and April 2020, they state: “The nationwide reaction to COVID-19 almost surely decreased the spread of the disease.” However, their results, they say, “have nothing to say about the health and societal benefits of staying at home and reducing physical contact with others.”
The model-based studies which claim stay-at-home lockdown orders saved thousands of lives are therefore in error, they argue.
The previously presented evidence on the effectiveness of SIP orders appears to be misleading, and there is currently no compelling evidence to suggest that SIP policies saved a large number of lives or significantly mitigated the spread of COVID-19. However, this does not mean that voluntary social distancing – SIP practice as distinct from policy – was ineffective.
The study was written and submitted prior to the appearance in Nature this March of the study by R.F. Savaris and colleagues which in effect looked at “SIP practice as distinct from policy”. It found that actually staying at home made little to no difference either:
We were not able to explain the variation of deaths per million in different regions in the world by social isolation, herein analysed as differences in staying at home, compared to baseline. In the restrictive and global comparisons, only 3% and 1.6% of the comparisons were significantly different, respectively.
I have noted before that it is important to be sceptical not just about lockdowns but about social distancing as well. This is because if the objection to lockdowns is simply that they’re unnecessary because people voluntarily lock themselves down anyway, and that it is this voluntary social isolation that stops the virus from spreading, then we are forced to agree with those who claim that the death toll so far is just a small part of what’s to come when social distancing ends and we all go back to mixing freely.
In other words, it is central to the sceptical argument that not just lockdowns but social distancing is largely ineffective at slowing or preventing the spread of SARS-CoV-2. Drop that and we have to admit that social distancing has so far prevented the population from feeling the full force of the pandemic and that returning to normal will bring a deadly new wave of infections (or concede that it is only vaccines that are keeping a ‘third wave’ at bay and that in the absence of the vaccines being invented we should all continue to socially isolate).
Of course, social distancing would be effective at preventing transmission if everyone actually isolated themselves completely. But the crucial point is that more often than not that doesn’t happen, particularly in contexts where the most vulnerable are located, in hospitals and care homes. With the main mode of transmission being via aerosols building up in the air of poorly ventilated spaces, staying two metres apart does nothing to protect from such exposure (and neither do masks).
The gap between what the published, peer-reviewed scientific literature says about lockdowns and what governments, their scientific advisers and the wider population believe about lockdowns is now very large. To have such a gap between data and scientific evidence on the one hand and public policy and social beliefs on the other is highly unstable and dangerous for a society. It results in intensifying social divisions as increasing numbers of people feel they cannot any longer go along with what the Government is saying, while on the other side the Government and its supporters increasingly resort to force and coercion because evidence and persuasion are not available to them. Yet admitting they are wrong is psychologically too difficult and personally too costly.
Professor Jay Bhattacharya recently came to the defence of his colleague Professor Sunetra Gupta, who had been attacked by a BBC interviewer for questioning the efficacy of lockdowns. He said: “There is a growing scientific consensus that the lockdowns have failed to control the spread of Covid in nearly every country that has imposed them.”
This is absolutely right. But the myth of lockdowns as an effective means of disease control persists anyway, and it is those who oppose them by quoting scientific evidence who are censored as dangerous and those who promote them by ignoring scientific evidence that are praised and listened to. It’s a topsy-turvy world, and a recipe for trouble.